A number that can be expressed as the signed sum of cubes in at least three ways: 2644883 + 3315743 - 3801933 =
23224043 - 8694183 - 22810573 = 4029063 - 2114023 - 3824893. [Rupinski]

The smallest prime such that another prime is never produced by inserting the same digit between each pair of its digits (40309, 41319, 42329, ... , 49399, are all composite). [Noll]

Take the sum of emirp 439 and its reversal: 439 + 934 = 1373. If we split 1373 in half and factor, we get 13*73 = 949 = 227+722 (a prime and its reversal). Note that 439+722 = 1161 = 934+227 uses each of the above primes and their reversals. [Bergot]

Robert Wadlow, the American who became famous as the
tallest person in recorded history, weighed 439 pounds at
his death.

(There are 5 curios for this number that have not yet been approved by an editor.)